The present invention relates generally to the intubation of patients for the internal administration or aspiration of fluids to a patient. More particularly, the present invention relates to a catheter tube and stylet assembly and an improved stylet for use with a catheter.
During various medical procedures, catheters are used for enteral feeding, urinary bladder drainage and irrigation, suctioning of blood and mucous, as well as for other purposes in the medical treatment of humans. The catheter is a flexible tube that must be placed through an orifice of the patient and advanced into the desired location. For example, during enteric therapy, a catheter or feeding tube is inserted through the nose of a patient and is carefully advanced into the patient's stomach or intestinal tract. Once properly positioned, fluids may be passed through the feeding tube and into the body of the patient. Often, these feeding tubes include a bolus having one or more apertures located therein in order to allow the fluids to pass from the feeding tube into the patient.
Since the catheter tube is relatively flexible, the rigidity of the catheter must be increased during the intubation process in order to allow for the insertion of the feeding tube into the patient. One approach is to increase the rigidity of the feeding tube through the use of a semi-rigid stylet removably mounted within the feeding tube. This approach allows the medical personnel to increase the rigidity of the feeding tube during the intubation process and thus assists in the proper placement of the feeding tube. Once the feeding tube is properly positioned within the patient, the stylet is removed from the feeding tube so that the feeding tube will become flexible again.
Two exemplary stylets are shown in U.S. Pat. No. 4,496,347 issued to MacLean et al. First, FIGS. 3 and 8-9 show a stylet formed from an elongate wire having a ball-shaped bead at its distal or insertion end. This stylet is disfavored because the bead may exit the feeding tube from the apertures within the bolus. Accordingly, the bead could strike a patient's tissues thereby causing injury. In addition, this stylet is more complex to manufacture than other known stylets because the ball-shaped bead must be separately attached to the wire.
A second known stylet is shown in FIGS. 5-7 of the '347 patent. This stylet is formed from a single strand of wire that is bent in half and twisted around itself in a double helix type formation. At the distal end of the stylet an elongated loop is formed from a single strand of wire. Generally, the loop has a length greater than the diameter of the apertures of the associated feeding tube in order to prevent the escape of the stylet from within the feeding tube. However, the loop may be easily deformed because it is formed from a single strand of wire. In particular, the side arms of the loop have no support and may be easily bent or distorted upon the application of pressure. As a result, the deformed loop may then exit the bolus and strike the tissues of a patient.
Accordingly, a need remains for a stylet that is easily manufactured and cannot be deformed so as to escape from within the associated catheter tube.